This invention relates to a coupling device having two parts and which is primarily intended for connecting two sections of an article of furniture, especially the connection of two panels in abutment and at right-angles to one another, the parts being securable to respective sections and being engageable when brought together so that the sections are securely held together.
Coupling devices of this kind, often referred to as "knock-down" fittings, are known and their principal use is for connecting two chipboard panels forming the side walls of cupboards or the like structures. Fittings are known in which the two parts have cooperating members, one of which includes an inclined or camming surface arranged to engage a part of the other member such that rotation of the first member produces a force on the second member whereby in use the two panels to which each member is respectfully connected are drawn together.
In one such coupling device (British Pat. No. 1447387) the two parts comprise a peg-like member adapted to be driven into a bore in the end of one panel and a cylindrical member for fitment into an aperture in the second panel. The peg member has a lug arranged to engage a recess in the other part and rotation of a screw causes an inclined camming surface to engage the lug whereby the first part is secured and drawn into the second part. A disadvantage of this device is that the peg is received in an end of the panel and if this comprises chipboard secure fixture therein is difficult. A further disadvantage is that the two coupling parts require different apertures and techniques for fitment into respective panels.
In another coupling device one part comprises a peg to be fixed into the edge of one panel with the head portion projecting, and a circular plate member received in a recess in a second panel towards an edge thereof with a transverse bore through from the edge into the recess. The plate member has a slot around its periphery which opens into an inwardly-facing involute curved surface. In use the peg of the one panel is passed through the aperture in the other panel and the head thereof engaged with the slot, whereupon rotation of the plate member causes the head to locate behind the involute surface and a camming action is thereby produced. In this device the plate member is loosely located in the recess and the aforementioned disadvantages apply also.
It is the primary object of this invention to provide an improved coupling device having two parts each of which may be received in similarly dimension apertures formed in the face of two respective panels and in which when said parts are assembled to the panels there are no significantly projecting pegs or the like, whereby the panels can be stacked for storage or transport with the parts fitted.
Further objects and advantages which accrue from specific and preferred embodiments according to the invention are that on locking the two parts together an expanding force is generated within one or both parts so that firm fixing within the apertures in the panels is ensured. Another object is to provide a coupling with no loose fittings such as screws or the like which require insertion before the coupling parts can be mated.